He suggested that the crocodile could be the same one that was seen at Pasir Ris Park earlier this month. Sightings of crocodiles, while not uncommon in areas such as Sungei Buloh Wetland Reserve in north-western Singapore, are much rarer in the north-eastern region.

NParks group director of parks Chia Seng Jiang said the board is aware of a recent sighting of a crocodile around Changi Beach Park and it is likely an estuarine crocodile.

Estuarine crocodiles are known to swim in the Straits of Johor. They feed and rest in mangroves and freshwater bodies, and are usually found in the water or at mudflats away from visitor routes.

Mr Chia said NParks is working with the AVA and the Animal Concerns Research and Education Society to monitor the sightings, as well as to catch and move the crocodile to another location, for the safety of park users.

"NParks and AVA have also advised vessel owners, fish farmers and operators of establishments along the coast to take the necessary precautions," he said.

Warning signs and advisory notices have been put up in the park near water edges.

"Visitors should heed these signs, in particular to keep to designated paths and away from water edges," said Mr Chia.

It also advised people who come across a crocodile to stay calm and back away slowly.

They should not approach, provoke or feed the animal, and can call the NParks helpline on 1800-471-7300 for assistance.